Ken Schug (IIT)
showed and passed around a most curious experiment. He mounted in
a small box (about 3x6 sq in), a piece of paper two lines of the
same words, one line directly below the other. Each line read:
URANIUM OXIDE, but on the top line the word OXIDE was
printed in red and in the bottom line, blue.
We took turns viewing the words through a glass
rod, about 3/8 inches diam and 3 inches long, held on the
paper, in direct contact with one line of words. When we
moved the rod down to the line below, we were amazed to
see that ...
Ed Scanlon (Morgan Park HS)
showed us how to change "orange juice" into a "strawberry float."
(handout) He placed a beaker with a solution in it into the middle
of a large tray. It had the color or orange juice. He then
quickly poured a colorless liguid into it, and it
immediately bubbled up and turned from orange to red!
Neat! But how does this work? Why does it happen!?
Ed told us the "orange juice" was made by mixing
100 gm baking soda into 200 ml water in a 500 ml beaker.
Add 3 good squeezes of dish soap and mix well. Add about
one tablespoon of glycerin and stir well. Add methyl
orange solution (an acid-base indicator) to give the
mixture an orange juice color. This was the "orange juice"
that we saw. It was orange in color because the baking
soda is basic, giving the solutin a pH greater than 7.
Methyl orange has an orange color in a basic solution.
When Ed added the colorless liquid, he was
adding about 100 ml of HCl to the "orange juice." The following
reaction occurred:
NaHCO3 + HCl -> NaCl + H2O + CO2 (gas).
The solution turns from basic to acid, shifting the pH to less than 7, and turning the color of the methy orange indicator to a pink-red, "strawberry." The CO2 bubbled up as a gas. Soap and glycerin mixtures are used for blowing bubbles that will last, so the bubbles foam up and it looks like a "soda." What a good way to motivate student interest in chemistry! Thanks, Ed!
Pam Moy (Morgan Park HS)
passed out materials to us, and described the membrane and fluid
mosaic model of a cell. With some guidance from Pam, we then used the
materials to create 2-D models of cells on paper, helping us to understand
better and remember this cell model. Very nice!
Karlene Joseph (Lane Tech)
showed us a part of a video tape of a Star Trek show. The
characters were involved in a discussion of what constitutes life, with
an android (synthetic "human") wondering about him-it-her self. Karlene
then got us involved in a very intertesting discussion of what constitutes
life and how ethics, science, and religious beliefs are all involvled in
such life issues as cloning, artificial reproduction of human cells, etc.
She certainly showed us how her students can be motivated; we certainly
were! Great!
Thanks to Pam Moy for the notes!